1. Field of the Invention
This invention relates to an improved flashing system for cavity wall structures, and more specifically for walls in which the inner wythe is masonry block and the outer wythe is brick.
2. Description of the Prior Art
In the past, investigations relating to cavity-based flashing systems for brick veneer masonry construction have demonstrated the advantages of surface-mounted flashing. While the technological strides have been made in flashing materials and in peel-and-stick technology, there still remain several areas where continued development is ongoing.
The inventors"" patents and their assignee""s product line are all related to accessories for cavity wall structures and include insulation, and anchoring and seismic devices, and are sold under the trademarks of Seismiclip(copyright), Byna-Tie(copyright), and DW-10-X(copyright). These products, which are manufactured by Hohmann and Barnard, Inc., Hauppauge, N.Y. 11788, have become widely accepted in the industry and have provided the inventors with particular insight into the technological needs of this marketplace.
Masonry walls with brick veneer are designed with an inner and an outer wythe and a cavity therebetween. The masonry block inner wythe and insulation thereon isolates the interior of the building from the environment, while the brick veneer outer wythe provides an aesthetic finish to the building. The walls of a building are constructed to exclude water and water vapor from the interior. Since the presence of excessive levels of water or water vapor in the cavity hastens the deterioration of building materials, various masonry flashing systems have been proposed.
Because of widespread usage and familiarity with bitumenous and asphaltic products in roofing applications, when masonry flashing systems were first designed, the building construction industry adopted the familiar copper and asphalt products. At that time the technology of pressure-sensitive hot melt adhesives needed for peel-and-stick applications was insufficiently developed. Some critics indicated that the adhesive quality was insufficient for the rough masonry block surfaces. Because of the presence of plasticizers, others were apprehensive about the available hot melt adhesives meeting the requisite fire retardancy standards. Also, to provide fire retardancy, some pressure-sensitive products were marketed for building construction use with inorganic fillers, such as alumina trihydrate, antimony oxide or calcium carbonate. However, these filled pressure-sensitive products had disadvantages, such as application problems, phase separation, toxicity, and reduced adhesion upon activation.
Prefabricated peel-and-stick flashing materials have been proposed, such as those shown in Harkness, U.S. Pat. No. 4,775,567 (see infra). These materials have included layers of bitumen and of compound bitumen for adhering the materials to the exteriors of masonry walls. While, under ideal circumstances, these peel-and-stick materials were easy to apply, the patent literature indicates that these materials did not conform well to irregular surfaces. Thus, the prior art bitumens used to secure these flashing materials to masonry walls often lacked the tackiness to bond tightly and durably to the wall surfaces. On occasion, when circumstances were not ideal, the bitumenous materials drooled marring the aesthetics of the brick veneer.
Despite these early efforts, developing the right combination of materials and methods for flashing cavity walls in a fast and efficient manner has proved elusive. In addition to the above described technical problems, because there is frequently a delay between erecting the inner wythe and the outer wythe, the flashing installed in the inner wythe is often exposed to substantial ultra-violet radiation. Thus, standards similar to ASTM Specification D4434-96 for polyvinyl chloride sheet roofing need to be met by masonry flashing systems.
In preparing for this application the following patents came to the attention of the inventors and are believed to be relevant to the further discussion of the prior art:
Oakleyxe2x80x94U.S. Pat. No. 6.224,700xe2x80x94Issued May 1, 2001
Oakley in U.S. Pat. No. 6,224,700 (assigned to Mar-Flex Systems, Inc., Middletown, Ohio) describes a method of applying a composite material to an above-grade building component to form a tacky non-swelling elastomeric membrane. Thereafter, a flexible, non-porous polymeric sheet is pressed onto the tacky exterior of the elastomeric membrane. The polymeric sheet is stronger than the elastomeric membrane and protects the elastomeric membrane from punctures or tears. Here, in situ construction is both labor intensive and requires special equipment for installation.
Pacificxe2x80x94U.S. Pat. No. 6,035,582xe2x80x94Issued Mar. 14, 2000
Pacific describes a flashing material which includes a sheet layer of copper, aluminum or other metal or a thin sheet of unreinforced plastic. Here it appears that in situ adhesives are applied.
U.S. Pat. No. 5,870,864xe2x80x94Snyderxe2x80x94Issued Feb. 16, 1999
Snyder describes a drainage system employing water collection pans which for insertion into the interior cavities of masonry block units over the length of a selected block wall course for collecting the water drained through the interior cavities of the upper courses and directing water to the exterior of the wall.
U.S. Pat. No. 5,860,259xe2x80x94Laskaxe2x80x94Issued Jan. 19, 1999
Laska describes an insulated drainage panel for use in cavity wall or veneer wall construction which panel includes a planar insulating board with a porous structure thereof.
U.S. Pat. No. 4,910,931xe2x80x94Parduexe2x80x94Issued Mar. 27, 1990
In the Pardue patent, a water collection and drainage system is described for a masonry block wall having bond beam block courses and intervening standard block courses. A system of upper water collection pans is supported along each upper bond beam course. Downspouts leading from drain openings in the upper collection pans drain collected from the pans through the vertical block cavities in lower block courses to the next lower series of collection pans. The lowermost bond beam course supports a series of base collection pans which collect water drained through the vertical block cavities from the upper collection pans. Weeping spouts lead laterally from the base collection pans to the exterior of the wall to continuously drain collected water from the interior wall cavities.
U.S. Pat. Nos. 4,775,567 and 4,775,409xe2x80x94Harknessxe2x80x94Issued Oct. 4,1988 and Jul. 5, 1988, Respectively.
A waterproofing laminate suitable for use in roofs, floors or other surfaces where waterproofing is desired contains a reinforcing sheet, first and second bitumen layers secured to opposite surfaces of the reinforcing sheet, first and second compound bitumen layers secured to the bitumen layers, an elastomeric sheet secured to the first compound bitumen layer and a release sheet secured to the second compound bitumen layer. Certain preferred materials for use in the laminate are recited.
U.S. Pat. Nos. 4,295,911 and 4,239,795xe2x80x94Haage et al.xe2x80x94Oct. 20, 1981 and Dec. 16, 1980, Respectively.
A protective covering for the protection of surface seals against mechanical damage in building constructions and other civil engineering constructions which comprises a composite of an elastic, waterproof thermoplastic synthetic resin film sheet and/or synthetic resin layer and a lattice-like fabric having knot couplings or points of intersection of the threads that yield under the effect of a load.
The use of a masonry flashing system of this invention includes a polymeric membrane with hot melt adhesive thereon, release paper, and drip plates for brick veneer facing, as described infra, has also been found to obviate the difficulties discussed and provides other advantages set forth herein.
In general terms, the masonry flashing system disclosed hereby includes a laminate for flashing which is particularly applicable to cavity walls such a wall with an inner wythe of masonry block and an outer wythe or veneer of brick. The masonry flashing system also includes a hot melt adhesive which coats a surface of the laminate. The adhesive is selected for compatibility with a peel-and-stick installation and, thus, upon pressure activation, when, for instance, the laminate with hot melt adhesive thereon is pressed against the rough surface of the masonry block, a durable bond is created. The laminate is constructed on a polymeric substate which in large part is a mixture of polyvinyl chloride and ethylene acetate carbon monoxide terpolymer. For purposes of improving puncture and tear resistance, a fibrous matxe2x80x94either woven or non-wovenxe2x80x94is embedded under a second elastomeric layer or cover.
Other components of the system include a stainless steel drip plate with a hot melt adhesive coating and a termination bar. The drip plate adhesive coating enables the installer to accurately position the plate and, during construction, maintain the alignment thereof. Optionally, a foam layer is placed on the lower surface of the drip plate so as to improve the sealing of the drip plate to the brick veneer.
The peel-and-stick technology shown herein enables quick and sure flashing of cavity walls which was unavailable prior to the advances in the materials of both elastomeric membranes and hot melt adhesives. The detailed description of these materials is provided hereinbelow.
It is an object of the present invention to provide in a masonry flashing system for cavity wall construction, a polymeric membrane with hot melt adhesive thereon which upon pressure activation strongly adheres to the rough and porous surfaces of masonry block and brick.
It is another object of the present invention to provide in a masonry flashing system for cavity wall construction, a polymeric membrane free of bituminous or asphaltic coatings, which membrane resists tearing and puncturing.
It is yet another object of the present invention to provide labor-saving masonry flashing system which utilizes peel-and-stick components that are easy and economical to install in cavity wall constructs having a masonry block inner wythe and a brick outer wythe.
It is still yet another object of the present invention to provide a masonry flashing system which operates cooperatively with present flashing accessories such as mortar guards and weep hole fittings.
It is a feature of the present invention that the hot melt adhesive hereof is compatible with flashing membranes containing ketone ethylene ester.
It is another feature of the present invention that the polymeric membrane hereof is highly, ultra-violet resistant and the membrane includes an embedded woven or non-woven fiber layer to enhance tear and puncture resistance.
It is yet another feature of the present invention that the drip plate optionally has hot melt adhesive portion thereon to assist in aligning the drip plate during the installation of the outer wythe.
Other objects and features of the present invention will become apparent upon reviewing the drawing and reading the detailed description which follows.